United States Department of Agriculture-Agricultural Research Service, Temperate Tree Fruit and Vegetable Research Unit, Wapato, WA.
Washington State University Extension, Vancouver, WA.
Environ Entomol. 2021 Feb 17;50(1):173-182. doi: 10.1093/ee/nvaa148.
Closely related phytophagous insects that specialize on different host plants may have divergent responses to environmental factors. Rhagoletis pomonella (Walsh) and Rhagoletis zephyria Snow (Diptera: Tephritidae) are sibling, sympatric fly species found in western North America that attack and mate on plants of Rosaceae (~60 taxa) and Caprifoliaceae (three taxa), respectively, likely contributing to partial reproductive isolation. Rhagoletis zephyria evolved from R. pomonella and is native to western North America, whereas R. pomonella was introduced there. Given that key features of the flies' ecology, breeding compatibility, and evolution differ, we predicted that adult eclosion patterns of the two flies from Washington State, USA are also distinct. When puparia were chilled, eclosion of apple- and black hawthorn-origin R. pomonella was significantly more dispersed, with less pronounced peaks, than of snowberry-origin R. zephyria within sympatric and nonsympatric site comparisons. Percentages of chilled puparia that produced adults were ≥67% for both species. However, when puparia were not chilled, from 13.5 to 21.9% of apple-origin R. pomonella versus only 1.2% to 1.9% of R. zephyria eclosed. The distinct differences in eclosion traits of R. pomonella and R. zephyria could be due to greater genetic variation in R. pomonella, associated with its use of a wider range of host plants than R. zephyria.
亲缘关系密切的专食性昆虫可能会对环境因素产生不同的反应，这些昆虫专门以不同的宿主植物为食。在北美洲西部，Rhagoletis pomonella (Walsh) 和 Rhagoletis zephyria Snow（双翅目：瘿蚊科）是近缘且同域分布的蝇种，它们分别攻击和交配于蔷薇科（约 60 个分类群）和忍冬科（3 个分类群）的植物，这可能促成了部分生殖隔离。Rhagoletis zephyria 是由 R. pomonella 进化而来的，且原产于北美洲西部，而 R. pomonella 则是被引入的。鉴于这些蝇类的生态学、繁殖相容性和进化的关键特征存在差异，我们预测来自美国华盛顿州的这两种蝇类的成虫羽化模式也会有所不同。当蛹被冷藏时，与雪果起源的 R. zephyria 相比，苹果和黑山楂起源的 R. pomonella 的羽化更为分散，高峰期不那么明显，无论是在同域还是非同域的地点比较中都是如此。两种蝇类的冷藏蛹产生成虫的比例均≥67%。然而，当蛹不被冷藏时，来自苹果起源的 R. pomonella 的羽化比例为 13.5%至 21.9%，而 R. zephyria 的羽化比例仅为 1.2%至 1.9%。R. pomonella 和 R. zephyria 在羽化特征上的显著差异可能是由于 R. pomonella 具有更大的遗传变异，与其利用更广泛的宿主植物范围有关，而 R. zephyria 则不然。
